1. Field of the Invention
The present invention relates to a bending sheath for a probe, by which a tip of the probe such as an ultrasonic probe or a laser probe inserted through a forceps channel of an endoscope inserted in a body cavity is bent.
2. Related Art Statement
Recently, there is developed an operation system in which a diagnosis and an operation in the body cavity are performed with the use of an endoscope. While in accordance with downsizing and diameter reduction of the ultrasonic probe and the laser probe, these probes are inserted through the forceps channel, and then diagnosis of and operation on a diseased part in a body cavity are performed.
In this case, in order to guide the probe such as the ultrasonic probe and the laser probe to the position of diseased part in the body cavity in place, in addition to suitable handling by handling portion of the endoscope, the bending operation of the probe tip portion must be performed properly.
As means for performing bending action of the probe tip properly, there are various methods, such as a method of bending the tip portion of the probe by pulling up a bending wire same as in the bending structure in general endoscope (Japanese Patent Application laid Open No. 38,342/93, first prior example), a method of using the shape memory alloy (Japanese Utility Model Application Laid Open No. 1,292/90, second prior example), and a method of bending the endoscope tip portion by pulling up the wire fixed to the tip portion, or the like. U.S. Pat. No. 5,306,245 (third prior example) discloses a construction that a hinge means is formed by cutting out the wall of an annular member, and an acting wire for performing a bending to the hinge side is provided, and U.S. Pat. No. 4,759,748 (fourth prior example) discloses a construction that a moving tube is inserted into a fixed tube, the tip portion of the moving tube protruded from the fixed tube is connected to a tip portion of the moving tube by a flexible member, and a shrinkage-proof member is provided to the flexible proof member.
Also, Japanese Patent Application laid Open No. 99,647/91 (fifth prior example) discloses a construction that an ultrasonic probe and a wire fixed to the tip portion of the ultrasonic probe are inserted in one catheter, and the probe tip portion is bent by drawing the wire.
Japanese Patent Application laid Open No. 269,134/93 (sixth prior example) discloses a construction that an ultrasonic probe and a beading sheath provided with a bent portion being bent by the pulling of the bending wire on the tip of a hard pipe, are combined.
As a means of detecting bent angle of the bending portion of the endoscope tip portion, a method of providing an encoder to the bending knob of the endoscope proximal end is well known.
However, since the above first prior example requires the radius fining of the bending wire in accordance with the radius fining of the probe, it is feared that the extension and wire breaking due to strength lacking for tension are caused, so that it is difficult to realize radius thinning of the probe, and to perform the action by the bending wire.
The above second prior example requires a driving circuit for driving SMA and means for controlling temperature, so that whole apparatus becomes complicated in construction.
In the above third prior example, since the wire provided to the hinge aide is bent by drawing action and the radius fining of the bending wire is required in accordance with the radius fining of the annular member, it is feared that the extension and wire breaking due to strength lacking for tension are caused, so that it is difficult to realize radius fining of the annular member and to realize an action due to the bending wire.
In the fourth prior example, respective constituent members are formed integrally, so that if a use of these components as a disposable article is taken into consideration, an expensive probe must be disposed together with other components, resulting in an expensive bending sheath.
In the fifth prior example, since the radius fining of the bending wire is required in accordance with the radius fining of the catheter, it is feared that the extension and wire breaking due to strength lacking for tension are caused, so that it is difficult to realize radius fining of the catheter and to realize an action due to the bending wire.
In the sixth prior example, the hard pipe is used, so that it is not a combination of it to the flexible endoscope. Moreover, a safe material for the living body must be utilized.